Re: anti-standard code can compile -- about template class

Thanks Bo Persson,

Can you explain why if we comment the line cout << d.get_i() << endl; in
main, there will not be compile error, but if we invoke cout << d.get_i() <<
endl;, there will be compile error?

From your points (I accept currently I agree), I can not explain. :-)

Any comments or ideas?

Compile errors,

1>------ Build started: Project: test_template4, Configuration: Debug Win32
------
1>Compiling...
1>main.cpp
1>d:\visual studio 2008\projects\test_template4\test_template4\main.cpp(20)
: error C2065: 'i' : undeclared identifier
1> d:\visual studio
2008\projects\test_template4\test_template4\main.cpp(20) : while compiling
class template member function 'int Derived<T>::get_i(void)'
1> with
1> [
1> T=int
1> ]
1> d:\visual studio
2008\projects\test_template4\test_template4\main.cpp(26) : see reference to
class template instantiation 'Derived<T>' being compiled
1> with
1> [
1> T=int
1> ]

[Code]
#include <iostream>

using namespace std;

template <typename T> struct Base {
public:
    Base (int _i): i (_i)
    {

    }

    int i;
};

template <typename T> struct Derived : public Base<T> {
public:
    Derived (int _i) : Base<T> (_i)
    {
    }
    int get_i() { return i; }
};

int main()
{
    Derived<int> d (200);
    cout << d.get_i() << endl; // output 200
    return 0;
}
[/Code]

regards,
George